The present invention relates to a line figure connecting apparatus for processing disconnections of input line figures.
A drawing apparatus is commercially available in which drawing information representing handwritten line figures is input and printed. In such a conventional drawing apparatus, read line figures are analyzed, and symbols and connections between a plurality of symbols are recognized.
When such graphic processing is to be performed, it is important to correctly recognize the input line figures. However, in practice, omissions often occur in the line figure itself to be processed, or omissions are often formed in the line figure due to poor precision of an image pickup device in the drawing apparatus. For these reasons, connection processing is performed for the omissions in the input line figures.
In conventional connection processing, the input line figure is thickened to connect the omissions and then the thickened figure is skeletonized to restore the original size.
In conventional connection processing, since the input line figure is entirely thickened, thin line segments of the input line figure, e.g., parallel lines, are undesirably combined. In addition, if there is a small hole in a line segment, which represents exclusion of a value at a point in the line segment, it is undesirably changed into a black dot. Assume that a line figure having an omission shown in FIG. 1A is subjected to connection processing to obtain a line figure shown in FIG. 1B. However, according to conventional processing, line segments having the same distance as a length of an omission are connected by line segment 1, and small hole 3 is undesirably expressed as a black dot, as shown in FIG. 1C.